Method and apparatus for finishing the edges of holes in metal plates



- Dec. 21, 1926. 1,611,839

c. F. MERRILL METHOD AND'APBARATUS FOR FINISHING THE EDGES OF HOLES IN METAL PLAIES Filed July-6". 1925 4 Sheets-Sheet' 1 W I ,w I

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Charles F. Merri ll M WKW ATTys.

Dec. 21 1926.

. c. F. MERRILL 7 METHOD AND APPARATUS FOR FINISHING THE EDGES OF HOLES IN METAL PLATES 4 Sheets-Sheet 2 Filed July 6. 1925 Fig.3.

I \nvenTor. Charles F. MerriH Dec. 21 1926.

c. F.' MERRILL METHOD AND APPARATUS FOR FINISHING 'I HE EDGES HOLES IN METAL'PLATES 1 Filed July 6 1925 4 Sheets-Sheet 5 I I' 6% m Fig.6.

, lhvenfor. Charles F Merrill byigw/wl Mk Patented Dec. 21,1926.

UNITED. STATES 1,611,839 PATENT OFFICE.

CHARLES E. MERRILL, OF HOPEDALE, MASSACHUSETTS, ASSIGNOR TO DRAPER COR- PORATION, HOPEDALE, MASSACHUSETTS, A CORPORATIDN OF MAINE.

METHOD AND APPARATUS FOR FINISHING THE EDGES OF HOLES IN' METAL PLATES.

Application filed July 6,

This invention relates to an apparatus and a process for the rounding off or the finishing of the edges of circular holes in metal plates. More particularly, the invention is designed for the rounding off or the finishing of the edges of the thread eye holes in steel drop wires such as are employed in the warp stop motions of looms. In such a warp stop motion, each warp is continually ree-ving through the hole of a drop wire, of which there are a very large number in a loom depending upon the number of ends. If either edge of the hole in the drop wire is rough or sharp, the tendency is to wear,

; and not infrequently to cut, the warp, thus delaying the weaving operation and requiring the piecing of the warp. These drop wires must be formed rapidly and economically and the hole or thread eye is usually formed by a punchin operation, which necessarily leaves the e ges in a more or less rough, sharp and unfinished condition.

The object of the present invention 1s to I provide an apparatus and a method by means of which the edges of such holes in such thin, metal plates may be rapidly, economically and uniformly finished so as to present smooth, rounded, convex edges which will not damage or injure the warp passing therethrough.

The nature and objects of the invention will appear more fully from the accompan ying description and drawings and will be particularly pointed out in the claims.

The drawings illustrate a simple and practical form of machine or apparatus embodying the invention and designed for carrying out the process of the invention, particularly in connection with the rounding ofl'; of the edges of the thread eyes in steel drop wires such as employed in the warp stop motions of looms.

In the drawings: I Fig.v 1 is a front elevation of the machine.

Fig. 2 is an end elevation looking toward the right of Fig. 1.

Fig. 3 is a top plan view of the machine.

.Fig. 4 is a View on a larger scale chiefly in horizontal cross section taken through the axis of one of the spindles and showing the main operative parts.

Fig. 5 is a detail showing the giveway connection between one of the grinding stones and its plunger.

Fig. 6 is a face view of a drop Wire.

1925. Serial No. 41,696.

Fig. 7 is a View on a greatly enlarged scale and partially broken away in transverse section showing the general shape of a punched hole in a fiat, metal plate or drop wire, the edges of which it is the object of the present invention to finish or round off.

Fig. 8 is a similar view after the left-hand Fig. .12 is a View similar to Fig. 8 showing the grinding stone in position at or near the conclusion of the operation. The machine herein illustrated for the purpose of disclosing a preferred embodiment of the present invention and a pre ferred means for carrying out the process 7 of the invention is of generally square shape.

The base 1 has rigidly secured thereto by the bolts 2 the 'verticalend plate standards 3 and 4, the top edges of which are connected atthe front and rear portions by the cover plates 5 and 6, held in place by the screws 7. Vertical, flanged, standard plates 8 and 9 at the front and 10 and 11 at the rear are rigidly secured by the bolts 12 to the cover plates and are in turn connected at the top respectively by the top plates 13 at the front and 14 at the rear, these top plates being secured to the top flanges of the standard plates by the screws 15. A pair of tie plates 16 connect the top plates 13 and 14 from front to rear and are secured thereto by the bolts 17. These tie plates in turn are connected by the plate 18, secured thereto by the bolts 19.

The main shaft 20, shown-as driven by a pulley 21 from a suitable source of power, extends centrally and transversely through the frame and is supported in bearings formed in brackets 22 and 23 formed on or rigidly secured to the end plate standards 3 and 4, respectively. This main shaft carries a spiral pinion 2-1 meshing with and driving the spiral gear 25, secured to a yer-1 formed upon or secured to a bracket 29, in turn secured by bolts 30 to a flange 31 on the end plate standard 3. This shaft 26 has also secured thereto above the gear 25 the grinder actuating cam 32- and below the gear another cam 33.

A skeleton sliding frame or slide 34, guided at the top in ways 35 formed in the top plates 13 and 14 and the guide arms 36 and 37 projecting respectively forward and rearward therefrom and at the bottom in ways 38 formed in the cover plates 5 and 6 and the guide arms 39 and 40 projecting respectively forward and rearward therefrom, is thus mounted for longitudinal reciprocation fore and aft of the frame. This slide is moved in one direction by a helical spring 41 connected at one end thereto and at its other end to a bracket 42 secured by the bolt 43 to the guide arm 40 and is moved in the other direction by the cam 32 engaging a follower roll 11 journalled on an arm 45 secured to the front end of the slide. This slide carries the grinding stones 46 and 47.

The construction of and the means for operating each grinding stone is the same, so that itis sutiicient to describe in detail but one, and for convenience the one at the front of the machine is illustrated, particularly in F ig. f. The slide 34 is formed to present aligned longitudinally supported bearings 1Sand49. These bearings are provided with bushings 50 and in these bushings is rotarily mounted a hollow, cylindrical spindle 51. At the inner end this spindle has secured thereto an apertured cap 52, and at'the outer end has threaded thereon another apertured cap 53. A pulley 54 is secured by means of a set screw 55 to the spindle between the bearings 48 and 49. This pulley is driven by a belt from any suitable source of power. The grinding stone 16, which may be an oil stone, is cylindrical in shape representing a pointed end 56, a cylindrical body 57, a cylindrical shank 5S. and a wedge-shaped end 59.. The shank 58 is somewhat larger than the body 57 forming at their juncture a shoulder 60. The grinding stone fits freely in the hollow spindle 51, so that it may move longitudinally and rotarily therein. Its longitudinal movement inwardly is limited by the engagement of the shoulder 60 with the apertured cap 52, through which the cylindrical body 57 projects. A drivin plunger is mounted in the hollow spindle to rotate therewith and slide with respect thereto. This plunger is shown as having a flattened or polygonal shank 61, sliding in a correspondingly shaped aperture in the cap 53 and a head 6: having a V-shaped face to fit over the wedge-shaped end 59 of the grinding stone. A helical spring 63 surrounds the shank of the plunger and is seated at one end against the head 62 and i at the other end against the cap 53. It will thus be seen that the driving plunger acts to force the grinding stone inwardly and also acts to secure the rotation of the grindin stone with the hollow spindle. The wedge-s aped end 59 of the grinding stone and the V-shaped face of the plunger constitute a giveway connection, so that if the grinding stone is prevented from rotation during the operation of the machine, the plunger will yield and rotate with the spindle independently of the grinding stone. As already noted, the construction at the rear of the machine with respect to these elements is the same and comprises a pulley 61, also driven by a belt from a suitable source of power and preferably at the same speed as the pulley 51. Since the spindles carrying the respective grinding stones have fixed longitudinal positions-in the slide 3- it will be seen that as the slide is reciprocated by means of the cam 32 and spring -11, the grinding stones are caused toperform their operation alternately.

The flat metal plates constituting the drop wires 65, the edges of the eyes 66 of which this machine is particularly designed to finish or round ofi', are supported in position for the grinding operation in a rigid supporting guide. This guide is shown as having a head 67 and an upstanding shank 6S adjustably secured by the set screw 69 in a boss 70 on the plate 18. The head 67 is slotted transversely to receive the drop wires and is apertured to allow the passage of the grinding stones.

Suitable means are provided for feeding the drop wires successively into position for the grinding operation. In the construction illustrated, the drop wires are supported in their passage into and out of the machine by a plurality of pairs of grooved feed wheels. Four pairs of such feed wheels are shown. Vertical brackets 71 and T2 are secured by bolts 73 to the top of the cover plates 5 and 6 on each side of the slide 31. The feed wheels 74 of the bottom row are carried by horizontal shafts 75 extending parallel with the axes of the grinding stones and journalled in the brackets 71 and 72. To each shaft is secured aspiral gear 76, held in place by a nut 77. These spiral gears 76 intermesh with complementary spiral gears 7 8 se-- cured to the main shaft 20, so that all of the lower set of feed wheels 74 are simultaneously driven in the same direction at the same speed. The upper cooperating feed wheels 7 9 are mounted respectively on shafts 80 arranged above and parallel with the shafts 75 and also having their bearings in the brackets 71 and 7:2. These upper feed wheels 79 are driven simultaneously and atthe same speed with the lower cooperating wheels by means of spiral gears 81 secured held downwardly by leaf springs '83 seand thefeed wheel 79 and cured to the bracket 71 and overlying the bearing blocks. Each shaft 80' is shouldered gear 81 are clamped between this shoulder and nut 84 threaded onto the shaft at the rear of the gear. v I

The drop wires are introduced successively between the feed wheels at the left of the machine and are fed thereby into such a position that the eye to be finished shall stand in axial alignment with the grinding stones or centered in the positioning guide 67. The endwise position of the drop wire is secured by a stop which is withdrawn from position after the grinding operation is completed, so as to allow the continued feeding movement of the drop wires and.

their discharge from the machine at the right. While a dro wire is thus held stationary for the grin ing operation, the feed wheels slip thereon. The stop is shown as a bar 85 guided near-its free end in a guide plate 86, This guide plate is adjustably secured to the bracket 71 by means of a clamping screw 87 passing-through a slot. in the guide. plate and threaded into the bracket. The bracket 71 is provided with an aperture 88 to permit the passage of the stop bar 85 therethrough and also a guide arm 89 extending from the guide plate 86, which abuts the-end of the drop wire and 'prevents bending thereof when the stop is .withdrawn. The stop is operated in timed relation to the rinding operation and thisis conveniently e ected by means of the cam 33. For this purpose, the stop bar 85 is pivotally connected at 90 to the arm 91 of a bell crank lever, the pivot of which is a vertical shaft 92 and the other arm 93 of which-has pivoted thereon'a follower roll 94 engaging the periphery of the 011111 This shaft 92 of the bell crank lever is pivotallymounted at its upper andlower ends in the arms of a bradret 95 secured to the end plate standard 3 by the bolts 96. A helical spring 97 coiled about the shaft 92 engages-at its upper end the bracket 95 and at its lower end the arm 93, and acts to maintain the follower roll 94in engagement with the periphery of the cam 33. Means are preferably provided for automatically feeding the drop wires successively chine.

to the feed wheels in timed relation with the grinding operation, and a simple and efli cient mechanism for this purpose is illustrate'd, particularly in Figs. 1 and 3. A bracket 98 is rigidly formed upon or secured to the end plate standard 4 and at the top projectshorizontally to the left of the mabolts 99 a pair of guide arms 100 and 101 projecting toward the/ front of the machine. A slide bar 102 is mounted in ways 'in'these guide arms and has rigidly secured thereto and extending parallel therewith a trough-shaped holder 103 adapted to receive and support a single drop wire in alignment with the passageway between the feed wheels. A bell crank lever has one arm 104 pivotally connected at 105 to a link 106, in

.turn pivotally connectedat 107 to the slide bar 102. The other arm 108 of this bell crank lever carries a. follower roll 109 adapted to cooperate with a cam projection 110 extending downwardly from the lower surface of the cam 33. This bell crank lever is fulcrumed on a shaft 111 mounted in projec- This bracket has secured thereto bytions 112 extending from'the end plate standard 4. A helical spring 113 secured at one end to a lug 114 on the guide arm 100 and at the other end to a projection 115 on the arm 104 of the bell crank lever, tends to hold the slide bar in its retracted position and the follower roll 109 in the path of the cam projection 110. The retracted position of the slide bar 102, and consequently of the trough holder 103, is adjustably determined by a set screw 116 threaded through the end plate standard 4 and engaging the downward prolongation 117 of the arm 104 of the bell crank lever, while the advanced position is determined by the engagement of this arm 104 with a stop lug 118 on the cover plate 5. The drop wires may be fed into the trough holder 103 either by hand or may slide thereinto from a suitable magazine or hopper when the slide bar 102 and trough holder'103 are in the retracted position.

The operation of the machine will be apparent from the foregolng description.

With power applied to the main pulley 21 and the grinding stone driving pulleys 54 and 64, at each revolution of the shaft 26 the cam projection 110 will slide the trough holder 103 to deliver, a'drop wire to the feed wheels 7 4 and 7.9; these feed wheels will advance the drop wire until its leading end engages the stop 85, thus positioning it with the eye 66 in axial alignment with the grinding stones and supported in the positioning holder 67; the slide 34 will be reciprocated by the cam 32 and spring 41 first in one direction'and then in the other, to cause the grinding stones 46 and 47 to act successively upon, and be withdrawn from contact with, the drop wire in performing the finishing operation; the stop 85 will then be withdrawn by the action of the cam 33 and the drop wire will then be discharged from the machine by the constantly Qrotating feed wheels.

\Vhile this invention is useful for finishing or rounding off the edges of circular holes in plates of metal of various size and quality, it has been particularly designed for use in the finishing of drop wires, and the principles involved are explained particularly in connection with this class of work.

Drop wires themselves vary somewhat in size and shape. An ordinary steel drop wire is about .008 inches in thickness and the diameter of the hole is about .250 inches, so

' that in illustrating such a drop wire, as in Figs. 712 of the drawings, on a large scale, it is necessary to show a considerable portion broken away. The thread eyes (:6 are usually formed by a punching operation, so

. that the peripheral edge 119 at one face of the drop wire presents a fairly smooth convex surface, due to the intrusion of the metal in the punching action, while the peripheral edge 120 at the opposite face is a ragged or uneven and more or less sharp fin, due to the extrusion of the metal in the'punching action.

It will be seen, therefore, that if the drop wires were continually presented succes-' sively in the same position to the grinding stones, one grinding stone would wear more than the other and the two edges of the drop wires would not be rounded off or finished symmetrically. The process of this invention contemplates, therefore, that the drop wires shallbe successively fed into the machine in alternating obverse and reverse positions. This will make the wear on each grinding stone the same and result in sym metrically rounded off or finished edges at both faces of the drop wires.

The action of the grinding stone upon the edge of the hole or thread eye 66 depends chiefly upon (1) the hardness of the metal of which the plates are formed, the condition of the edges of the holes, i. 0., whether the edge has a sharp, ragged fin due to the extrusion of the metal, or whether it is comparatively smooth and indented due to the intrusion of the metal by the punching operation, the quality, i. e., the hardness and tenacity of the grinding stones, (4) the rapidity of the cutting. action depending upon the speed of the grinding stones and the speed of the feeding movement between them and the plates, (5) the pressure of the grinding stones against the plates and, ,(6) the excess in the diameter of the cylindrical l-odies 57 of the grinding stones over the diameter of the holes themselves.

()ne of the most important factors in the operation is that last referred to, namely, .the diameter of the grinding stones as related to the diameter of the hole to be finished.

It is found in practice that if the thickness of the shoulder on the grinding stone. indicated at 121 in Fig. 12, be about equal to the thickness of the drop wire which nieans that the diameter of the cylindrical body 57 exceeds the diameter of the hole in the drop wire by twice the thickness of the drop wire, the diameter of the hole will not be materially enlarged in the grinding operation and both edges will be. rounded or finished OH in flat, smooth, convex curves as shown in Fig. 9. One edge will be finished off, as shown in Fig. 8 with the opera-- tion of the first grinder and then the second edge will be finished off to bring the wire into the condition shown in Fig. 5). If this shoulder 121 be increased to twice the thickness of the drop wire, so that the diameter of the cylindrical body of the grinding stone exceeds the diameter of the hole by four times the thickness of the drop wire, a very satisfactory result. still ensues, both edges being finished off in wide, flat, convex curves, as shown in Fig. 10. Ifthe shoulder 121 be reduced to one-half the thickness of the drop wire and the cylindrical body of the grinding stone has a diameter exceeding the diameter of the hole by the thickness of the drop wire, then it is found that the grinding operation performed by the first grinding stone removes metal well past the central plane of the drop wire, so that the second grinding stone in its action removes less metal, but by reversing the drop wires, the symmetry of the edges is maintained, but the diameter of the hole or thread eye is enlarged. The result is a finished product substantially as shown in Fig. 11. In practice, therefore, the width of the shoulder 121, under ordinary conditions, should be equal to the thickness of the drop wire and may range from onehalf the thickness of the drop wire to twice the thickness of'the drop wire and secure satisfactory results. While this range is believed to be the most practical, the invention is not to be understood to be definitely limited thereto.

It is found .by correlating the factors named, which may readily be done by controlling the speeds and the width of the shoulder on the grinding stones, that the face of this annular shoulder on each grinding stone will immediately wear into a concavity complementary to the desired convex form of the edge of the hole in the drop wire. and, that as the operation proceeds, the

loitogether, as in natural oil stones and ce- The grinding elements of this invention are designated herein as grinding stones, but

this term stone, in the sense herein used,-

is to be takenas including natural orartificial abrasives which are stone-like in their character. Such abrasives, when in a form suitable for use in this invention, are more specifically an agglomeration of-crystals or sharp particles more or less securely bonded mented compositions, or a'spongy, vitreous mass like umice, as in the case of some of the artificial oil stones.

The essential feature is that the grinding stones, whether of natural or of artificial origin, shall have the qualities necessary to cause them to function in accordance with the principles hereinbefore defined. An oil stone has been found to embody the qualities which permit the application of these principles, but any rigid mass of granular or spongy abrasive material that will wear away by the release of its particles, continually re-forming the shoulder in accordance with the principles of the invention, is a satisfactory grinding stone for the purpose of this invention. a y

The grinding o eration may be performed in the presence 0 a suitable lubricant which the axis of the hole, a grinding stone having a pointed end and a cylindrical body of such a diameter in excess of the diameter of the hole that the grinding action forms and wears back a uniform, concave, annular shoulder on the stone and in turn forms a corresponding convex edge on the hole of each late. v 7

2. he process of. rounding off the edges of similar circular-"holes in metal plates which consists in simultaneously rotating and forcing into the holes successively, while maintaining it on an axis in alignment with the axis of the hole, a grinding stone having a pointed end and a cylindrical body of a diameter in excess of that of the holes and in correlatin the hardness of the metal of the plates, t e condition of the edges of the holes, the hardness and tenaclty of the grinding stones, the. rapidity of the cutting action, the pressure of the grinding stones against the plates'and the excess in the diameter of the cylindrical bodies, of

the grinding stones over the diameter of the holes to cause the edgesof the holes to be rounded elf symmetrically on a convex curve and a uniform, similar, annular shoulderof complementary concavity to be worn back on each proceeds.

3. The process of rounding oil .the edges of similar punched, circular holes in a series grinding stone as the operation of similar metal plates which consists in '75 presenting the plates successively in alternating obverse and reverse positions with. the axes of the holes in substantial alignment with the aligned axes of two oppositely disposed, longitudinally reciprocable and rotatable, similar, pointed, cylindrical, grinding stones having diameters slightly greater than the diameter over all of the metal of the plates extruded and intruded in the punching operation, and in reciprocating the grinding stones while rotating alternately into and out of each hole as presented thereto to cause the edges of the holes to be rounded ofl' symmetrically on a convex curve and a uniform, simllar, annular shoulderv of complementary concavity to be Worn back on each grinder as the operation proceeds.

4. The process of rounding ofi the edges of similar punched circular holes in a series of similar metal plates which consists in presenting the plates in alternating obverse and reverse positions with the axes of the holes in substantial alignment with the axis of a longitudinally reciprocable and rotatable, pointed, cylindrical grindin stone having a diameter slightly greater than the, diameter over all of the metal of the plates extruded and intruded *in the punching operation and in reciprocatin while rotating into'and out o each hole as presented thereto to cause the edges of the oles thus presented to be rounded off symmetrically on a convex curve and a uniform,"

annular shoulder of complementary concavity to be worn back on the grinder as the operation proceeds. v

5. A machine for rounding ofi the edges of similar circular holes in similar metal plates comprising a grinding stone having a pointed end and a cylindrical bodyof a diameter equal to, the diameter of the holes. plus from one to four times the thickness: of the plates, and means for simultaneously efifecting relative rotation and longitudinal'lzo movement. successively between each plate and the grinding stone, while maintaining the hole and grindipg stone in axial alignment, to cause the' to be; worn back on each grindmg stone.

.6. A'machine ferrounding'ofithe edges. "of similar circular holes. in similar metal {ID the grinder 105 ges of the holes to be rounded ofi symmetrically on a' onvex curve and a uniform, similar, annular s oulder of I complementarv concavity ment with the s indle and for rigidily supporting them w en in aligned position, and

means for reciprocating the slide when a plate is in aligned position to force the grinding stone into yielding engagement with the edge of the hole 'to round off the v of the spindle,

said edge and then to retract the stone.

7. A machine for rounding off the edges of similar circular holes in similar metal plates comprising. a longitudinally reciproicable slide, a hollow spindle rotarily mounted in the slide, means for rotating the spindle, a cylindrical grinding stone 1 rotatable and longitudinally slidable in the spindle and having a shoulder to limit the projection of its grinding end fromthe end a driving plunger mounted in the spindle to rotate therewith and slide with respect thereto, a spring for yieldingly forcing the plunger against the rear end of the grinding stone, a giveway connection cylindrical grinding stone' between the plunger and the stone, acting in conjunction with the spring to cause the stone to rotate with the plunger under nor; mal conditions and to permit non-rotation of the stone with the plunger upon the occurrence of an abnormal resistance to the stone, means for feeding metal plates having similar circular holes therein to bring the holes into'axial alignment with the spindle and for rigidly supporting them when in aligned position, and means for reciprocating the slide when a plate is in aligned positionto force the grinding stone into yielding engagement with the edge of the hole to round ofi' the said edge and then to retract the stone.

8. A machine for rounding ofi the edges of similar circular holes in similar metal plates comprising a cylindrical grinding stone, means for rotating the stone, means for intermittently projecting the stone yieldingly in the direction of its axis and for then retracting it, means for successively feedingmetal plates having similar circular holes therein to bring the holes into axial alignment with the stone, and means for rigidly supporting the plates when in aligned position.

In testimony whereof, I have signed my name to this specification.

CHARLES F. MERRILL. 

